Systems and methods for determining inventory using time-slotted tag communications

ABSTRACT

Systems and methods for determining an inventory. The methods comprise: placing an RFID tag in a first operational mode in which at least one communication operation or device of the RFID tag is disabled or bypassed; performing first operations by the RFID tag to determine when it is time to begin communications in accordance with the time slotted communications scheme; transitioning an operational mode of the RFID tag from the first operational mode to a second operational mode in which the communication operation(s) or device of the RFID tag is enabled or no longer bypassed, in response to a determination that it is time for the RFID tag to begin communications; and transitioning the operational mode of the RFID tag back into the first operational mode when the RFID tag&#39;s communications with a remote tag reader for inventory determination purposes are complete or a time slot has expired.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Applicationhaving Ser. No. 62/565,350 which was filed on Sep. 29, 2017 and isincorporated herein in its entirety.

BACKGROUND Statement of the Technical Field

The present disclosure relates generally to Radio FrequencyIdentification (“RFID”) systems. More particularly, the presentdisclosure relates to implementing systems and methods for determininginventory using time slotted tag communications.

Description of the Related Art

Inventory solutions often use passive RFID tags because of their size,cost and mature infrastructure. However, passive RFID was never designedto support the vast number of tags, long read range, large number ofreaders, fast response times, location detection, and the high accuracyneeded for a real-world solution.

Battery Assisted Passive (“BAP”) RFID tags greatly help with the readrange (increasing the read range from, for example, 1-10 meters to15-100 meters) but also increase size, cost and complexity. In addition,the batteries must be replaced.

SUMMARY

The present disclosure generally concerns implementing systems andmethods for determining an inventory. The methods comprise: placing anRFID tag in a first operational mode in which at least one communicationoperation or device of the RFID tag is disabled or bypassed; performingfirst operations by the RFID tag to determine when it is time to begincommunications in accordance with the time slotted communicationsscheme; transitioning an operational mode of the RFID tag from the firstoperational mode to a second operational mode in which the at least onecommunication operation or device of the RFID tag is enabled or nolonger bypassed, in response to a determination that it is time for theRFID tag to begin communications; and transitioning the operational modeof the RFID tag back into the first operational mode when the RFID tag'scommunications with a remote tag reader for inventory determinationpurposes are complete or a time slot has expired.

In some scenarios, the first operational mode comprises a powerrecharging mode in which a rechargeable power source is charged usingharvested ambient energy.

In those or other scenarios, the methods also comprise assigning atleast one first time slot of a plurality of time slots to each RFID tagof a plurality of RFID tags in accordance with the time slottedcommunication scheme. The at least one time slot is assigned to the RFIDtag based on the RFID tag's unique code. The RFID tag's unique codeincludes, but is not limited to, an Electronic Product Code (“EPC”), aCyclic Redundancy Check (“CRC”) code, a hash code or output of arandomizing algorithm. Alternatively or additionally, the at least onetime slot is assigned to the RFID tag based a chaotic, random orpseudo-random algorithm.

The RFID tag performs communication operations in time slots of theplurality of time slots that are allocated to other RFID tags, when theRFID tag is in motion. The communication operations are discontinuedwhen motion is no longer detected, a power source of the RFID tag has acertain level of charge, or a control signal for disabling or bypassingthe communication operations is received from an external device.

In those or other scenarios, a motion sensor detects motion of the RFIDtag. Output data of the motion sensor is used to: (a) trigger anoperational mode change by the RFID tag when the RFID tag is in motion;or (b) determine if the detected motion is of a type for triggeringcommunication operations or device enablement. In scenario (b), theoperational mode of the RFID tag is transitioned from the firstoperational mode to the second operational mode, in response to adetermination that the detected motion is of a type for triggeringcommunication operations or device enablement. The RFID tag may notifythe remote tag reader that motion has been detected by the motionsensor.

In those or yet other scenarios, the RFID tag is transitioned back intothe first operational mode when a window of time has expired. A value ofthe window of time is variable. The value of the window of time isdynamically determined based on at least one of an environmentalcondition and the system operational condition.

BRIEF DESCRIPTION OF THE DRAWINGS

The present solution will be described with reference to the followingdrawing figures, in which like numerals represent like items throughoutthe figures.

FIG. 1 is an illustration of an illustrative architecture for a system.

FIG. 2 is an illustration of an illustrative architecture for a tag.

FIG. 3 is an illustration of an illustrative architecture for a tagreader.

FIG. 4 is an illustration of an illustrative architecture for a server.

FIG. 5 is an illustration of an illustrative tag reader configuration.

FIG. 6 is an illustration of another illustrative tag readerconfiguration.

FIGS. 7A-7B (collectively referred to herein as “FIG. 7”) provideillustrations that are useful for understanding an inventory cycle countusing time slots for communications between tag readers and tags.

FIG. 8 is a flow diagram of an illustrative method for an inventorycycle count using time slots for communications between tag readers andtags.

FIG. 9 is an illustration that is useful for understanding an inventorycycle count in which (a) time slots are used for communications betweentag readers and tags and (b) a detection of tag motion causescommunication enablement.

FIG. 10 is an illustration of a tag response message.

FIG. 11 is an illustration of another tag response message.

FIGS. 12A-12B (collectively referred to herein as “FIG. 12”) provide aflow diagram of an illustrative method for an inventory cycle count.

DETAILED DESCRIPTION

It will be readily understood that the components of the embodiments asgenerally described herein and illustrated in the appended figures couldbe arranged and designed in a wide variety of different configurations.Thus, the following more detailed description of various embodiments, asrepresented in the figures, is not intended to limit the scope of thepresent disclosure, but is merely representative of various embodiments.While the various aspects of the embodiments are presented in drawings,the drawings are not necessarily drawn to scale unless specificallyindicated.

The present solution may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the present solution is, therefore,indicated by the appended claims rather than by this detaileddescription. All changes which come within the meaning and range ofequivalency of the claims are to be embraced within their scope.

Reference throughout this specification to features, advantages, orsimilar language does not imply that all of the features and advantagesthat may be realized with the present solution should be or are in anysingle embodiment of the present solution. Rather, language referring tothe features and advantages is understood to mean that a specificfeature, advantage, or characteristic described in connection with anembodiment is included in at least one embodiment of the presentsolution. Thus, discussions of the features and advantages, and similarlanguage, throughout the specification may, but do not necessarily,refer to the same embodiment.

Furthermore, the described features, advantages and characteristics ofthe present solution may be combined in any suitable manner in one ormore embodiments. One skilled in the relevant art will recognize, inlight of the description herein, that the present solution can bepracticed without one or more of the specific features or advantages ofa particular embodiment. In other instances, additional features andadvantages may be recognized in certain embodiments that may not bepresent in all embodiments of the present solution.

Reference throughout this specification to “one embodiment”, “anembodiment”, or similar language means that a particular feature,structure, or characteristic described in connection with the indicatedembodiment is included in at least one embodiment of the presentsolution. Thus, the phrases “in one embodiment”, “in an embodiment”, andsimilar language throughout this specification may, but do notnecessarily, all refer to the same embodiment.

As used in this document, the singular form “a”, “an”, and “the” includeplural references unless the context clearly dictates otherwise. Unlessdefined otherwise, all technical and scientific terms used herein havethe same meanings as commonly understood by one of ordinary skill in theart. As used in this document, the term “comprising” means “including,but not limited to”.

There is a need for a solution that improves the read range of a passiveRFID tag while keeping size, cost and response time low. In addition,the solution can advantageously include a very small, rechargeable powersource (e.g., battery or capacitor) so that it keeps the cost and sizelow, and eliminates the need for battery changes. Low cost versions canuse a non-rechargeable battery when a fixed battery has enough energy tolast for the lifetime of the RFID tagged product.

The present solution generally concerns systems and methods fordetermining inventory using time slotted tag communications. The presentsolution solves the following problems:

how to have a battery assisted passive RFID tag without constant batterydrain caused by constant inventory reading which is needed to monitortag motion and for full inventory count;

how to have a battery assisted passive RFID tag with great read rangewithout having very large numbers of tags constantly attempting tocommunicate causing delays and communication collisions;

how to have a battery assisted passive RFID tag that can still be readoften enough for a full inventory count in an area; and

how to enable detection of a tag that is being moved or stolen.

The present solution can use standard RFID tags and readers (with asoftware update) but could be designed to incorporate the functioninginto a new and compatible RFID tag chip as well. Initially, the RFID tagwould need to be supplemented with a rechargeable power source (e.g., abattery and/or a capacitor), a Central Processing Unit (“CPU”), anaccelerometer and/or motion detector.

Just as in normal RFID implementations, RFID tag readers are constantlyscanning their Field Of View (“FOV”) and requesting that all tags in itscoverage area respond to interrogation signals. The present solutionsolves these problems with two novel features: (A) time based RFID tagcommunications control (e.g., disabling a receiver, disabling atransceiver or transmitter, disabling a communications operation,bypassing a communications device or operation, and/or disabling aresponse from the RFID tag); and (B) motion based RFID tagcommunications control. The RFID tag control of (A) involves controllingthe RFID tag so that it only enables its communications functionality(e.g., enables a receiver, enables a transceiver or transmitter, enablesat least one communications operation, and/or discontinues a bypass of acommunications device or operation) periodically under system control.This is for improved static inventory counting. The RFID communicationscontrol of (B) involves turning on, enabling or no longer bypassing theRFID receiver, the RFID transceiver/transmitter and/or at least onecommunications operation when motion is detected and continuing toreceive interrogation signals while in motion. This is for lossprevention and tag location tracking.

Novel feature (A) provides better full inventory counts. In the presentsolution, the RFID chip is scheduled to only enable (or turn on) or nolonger bypass its communication device (e.g., a transceiver) orcommunications operation(s) one or two times a day, and to disable (orturn off) or bypass its communication device (e.g., transceiver) orcommunications operation(s) after communication with a tag readercompletes or a timing window expires. The timing of the RFID tagcommunications is distributed over a given time period (e.g., a day or24 hours) so that any time slot will only be assigned to a very smallpercentage of the RFID tags. This enables fast reading cycles, minimizescommunications collisions, and enables identifying every tag.

Novel feature (A) also vastly reduces the RFID tags' battery drain. Themain power drain on the battery is from the receiver and CPU. In thepresent solution, these components are only active for a few seconds perday (out of 86,400 seconds). The rest of the time the RFID tags cancapture energy for charging the battery from the received RF energy andother sources of energy harvesting. This allows for a very small, lowcost rechargeable battery or capacitor. A rechargeable energy storage isnot required. For some applications, a primary battery (e.g., a lithiumcoin cell) can be used without recharging. If a small battery can supplyenergy for the expected life time of the tag, then a fixed battery couldbe used to reduce the costs. For example, a swing ticket could have asmall battery that lasts less than one year.

Novel feature (A) further improves tag read range which reducesinfrastructure costs. Using battery assisted tags changes the tag readrange from, for example, 1-10 meters to 15-100 meters. Thissignificantly reduces infrastructure installation costs since less tagreaders are needed to cover a given area as compared to that needed inconventional systems, while improving overall performance in previouslyhard to read areas.

Novel feature (B) ensures that tags in motion respond to interrogationsignals even at times when they are not scheduled to communicate duringtime slots. The system can now track an RFID tag while it is in motionand also detect where/when this tag motion stops. Novel feature (B) alsofacilitates better inventory counts, improved read ranges, and reducedinfrastructure costs.

Illustrative Systems

Referring now to FIG. 1, there is provided a schematic illustration ofan illustrative system 100 that is useful for understanding the presentsolution. The present solution is described herein in relation to aretail store environment. The present solution is not limited in thisregard, and can be used in other environments. For example, the presentsolution can be used in distribution centers, factories and othercommercial environments. Notably, the present solution can be employedin any environment in which objects and/or items need to be locatedand/or tracked.

The system 100 is generally configured to allow improved inventorycounts of objects and/or items located within a facility. As shown inFIG. 1, system 100 comprises a Retail Store Facility (“RSF”) 128 inwhich display equipment 102 ₁, . . . , 102 _(M) is disposed. The displayequipment is provided for displaying objects (or items) 110 ₁-110 _(N),116 ₁-116 _(X) to customers of the retail store. The display equipmentcan include, but is not limited to, shelves, article display cabinets,promotional displays, fixtures and/or equipment securing areas of theRSF 128. The RSF can also include emergency equipment (not shown),checkout counters and an EAS system (not shown). Emergency equipment,checkout counters, video cameras, people counters, and EAS systems arewell known in the art, and therefore will not be described herein.

At least one tag reader 120 is provided to assist in counting theobjects 110 ₁-110 _(N), 116 ₁-116 _(X) located within the RSF 128. Thetag reader 120 comprises an RFID reader configured to read RFID tags.RFID readers are well known in the art, and therefore will not bedescribed herein. Any known or to be known RFID reader can be usedherein without limitation.

RFID tags 112 ₁-112 _(N), 118 ₁-118 _(X) are respectively attached orcoupled to the objects 110 ₁-110 _(N), 116 ₁-116 _(X). The RFID tags aredescribed herein as comprising single-technology tags that are only RFIDenabled. The present solution is not limited in this regard. The RFIDtags can alternatively or additionally comprise dual-technology tagsthat have both EAS and RFID capabilities.

Notably, the tag reader 120 is strategically placed at a known locationwithin the RSF 128. By correlating the tag reader's RFID tag reads andthe tag reader's known location within the RSF 128, it is possible todetermine the location of objects 110 ₁, . . . , 110 _(N), 116 ₁, . . ., 116 _(X) within the RSF 128. The tag reader's known coverage area alsofacilitates object location determinations. Accordingly, RFID tag readinformation and tag reader location information is stored in a datastore 126. This information can be stored in the data store 126 using aserver 124. Server 124 will be described in more detail below inrelation to FIG. 4.

Referring now to FIG. 2, there is an illustration of an illustrativearchitecture for a tag 200. RFID tags 112 ₁, . . . , 112 _(N), 118 ₁, .. . , 118 _(X) are the same as or similar to tag 200. As such, thediscussion of tag 200 is sufficient for understanding the RFID tags 112₁, . . . , 112 _(N), 118 ₁, . . . , 118 _(X) of FIG. 1. Tag 200 isgenerally configured to perform operations to (a) minimize power usageso as to extend a power source's life (e.g., a battery or a capacitor),(b) minimize collisions with other tags so that the tag of interest canbe seen at given times, (c) optimize useful information within aninventory system (e.g., communicate useful change information to a tagreader), and/or (d) optimize local feature functions.

The tag 200 can include more or less components than that shown in FIG.2. However, the components shown are sufficient to disclose anillustrative embodiment implementing the present solution. Some or allof the components of the tag 200 can be implemented in hardware,software and/or a combination of hardware and software. The hardwareincludes, but is not limited to, one or more electronic circuits. Theelectronic circuit(s) may comprise passive components (e.g., capacitorsand resistors) and active components (e.g., processors) arranged and/orprogrammed to implement the methods disclosed herein.

The hardware architecture of FIG. 2 represents a representative tag 200configured to facilitate improved inventory management. In this regard,the tag 200 is configured for allowing data to be exchanged with anexternal device (e.g., tag reader 120 of FIG. 1 and/or server 124 ofFIG. 1) via wireless communication technology. The wirelesscommunication technology can include, but is not limited to, a RadioFrequency Identification (“RFID”) technology, a Near Field Communication(“NFC”) technology, and/or a Short Range Communication (“SRC”)technology. For example, one or more of the following wirelesscommunication technologies (is)are employed: Radio Frequency (“RF”)communication technology; Bluetooth technology; WiFi technology; beacontechnology; and/or LiFi technology. Each of the listed wirelesscommunication technologies is well known in the art, and therefore willnot be described in detail herein. Any known or to be known wirelesscommunication technology or other wireless communication technology canbe used herein without limitation.

The components 206-214 shown in FIG. 2 may be collectively referred toherein as a communication enabled device 204, and include a memory 208and a clock/timer 214. Memory 208 may be a volatile memory and/or anon-volatile memory. For example, the memory 208 can include, but is notlimited to, Random Access Memory (“RAM”), Dynamic RAM (“DRAM”), StaticRAM (“SRAM”), Read Only Memory (“ROM”) and flash memory. The memory 208may also comprise unsecure memory and/or secure memory.

In some scenarios, the communication enabled device 204 comprises aSoftware Defined Radio (“SDR”). SDRs are well known in the art, andtherefore will not be described in detail herein. However, it should benoted that the SDR can be programmatically assigned any communicationprotocol that is chosen by a user (e.g., RFID, WiFi, LiFi, Bluetooth,BLE, Nest, ZWave, Zigbee, etc.). The communication protocols are part ofthe device's firmware and reside in memory 208. Notably, thecommunication protocols can be downloaded to the device at any giventime. The initial/default role (being an RFID, WiFi, LiFi, etc. tag) canbe assigned at the deployment thereof. If the user desires to useanother protocol at a later time, the user can remotely change thecommunication protocol of the deployed tag 200. The update of thefirmware, in case of issues, can also be performed remotely.

As shown in FIG. 2, the communication enabled device 204 comprises atleast one antenna 202, 216 for allowing data to be exchanged with theexternal device via a wireless communication technology (e.g., an RFIDtechnology, an NFC technology and/or a SRC technology). The antenna 202,216 is configured to receive signals from the external device and/ortransmit signals generated by the communication enabled device 204. Theantenna 202, 216 can comprise a near-field or far-field antenna. Theantennas include, but are not limited to, a chip antenna or a loopantenna.

The communication enabled device 204 also comprises a communicationdevice (e.g., a transceiver or transmitter) 206. Communication devices(e.g., transceivers or transmitters) are well known in the art, andtherefore will not be described herein. However, it should be understoodthat the communication device 206 generates and transmits signals (e.g.,RF carrier signals) to external devices, as well as receives signals(e.g., RF signals) transmitted from external devices. In this way, thecommunication enabled device 204 facilitates the registration,identification, location and/or tracking of an item (e.g., object 110 or112 of FIG. 1) to which the tag 200 is coupled.

The communication enabled device 204 is configured so that it:communicates (transmits and receives) in accordance with a time slotcommunication scheme; and selectively enables/disables/bypasses thecommunication device (e.g., transceiver) or at least one communicationsoperation based on output of a motion sensor 250. In some scenarios, thecommunication enabled device 204 selects: one or more time slots from aplurality of time slots based on the tag's unique identifier 224 (e.g.,an Electronic Product Code (“EPC”)); and/or determines a Window Of Time(“WOT”) during which the communication device (e.g., transceiver) 206 isto be turned on or at least one communications operation is be enabledsubsequent to when motion is detected by the motion sensor 250. The WOTcan be determined based on environmental conditions (e.g., humidity,temperature, time of day, relative distance to a location device (e.g.,beacon or location tag), etc.) and/or system conditions (e.g., amount oftraffic, interference occurrences, etc.). In this regard, the tag 200can include additional sensors not shown in FIG. 2.

The communication enabled device 204 also facilitates the automatic anddynamic modification of item level information 226 that is being or isto be output from the tag 200 in response to certain trigger events. Thetrigger events can include, but are not limited to, the tag's arrival ata particular facility (e.g., RSF 128 of FIG. 1), the tag's arrival in aparticular country or geographic region, a date occurrence, a timeoccurrence, a price change, and/or the reception of user instructions.

Item level information 226 and a unique identifier (“ID”) 224 for thetag 200 can be stored in memory 208 of the communication enabled device204 and/or communicated to other external devices (e.g., tag reader 120of FIG. 1 and/or server 124 of FIG. 1) via communication device (e.g.,transceiver) 206 and/or interface 240 (e.g., an Internet Protocol orcellular network interface). For example, the communication enableddevice 204 can communicate information specifying a timestamp, a uniqueidentifier for an item, item description, item price, a currency symboland/or location information to an external device. The external device(e.g., server) can then store the information in a database (e.g.,database 126 of FIG. 1) and/or use the information for various purposes.

The communication enabled device 204 also comprises a controller 210(e.g., a CPU) and input/output devices 212. The controller 210 canexecute instructions 222 implementing methods for facilitating inventorycounts and management. In this regard, the controller 210 includes aprocessor (or logic circuitry that responds to instructions) and thememory 208 includes a computer-readable storage medium on which isstored one or more sets of instructions 222 (e.g., software code)configured to implement one or more of the methodologies, procedures, orfunctions described herein. The instructions 222 can also reside,completely or at least partially, within the controller 210 duringexecution thereof by the tag 200. The memory 208 and the controller 210also can constitute machine-readable media. The term “machine-readablemedia”, as used here, refers to a single medium or multiple media (e.g.,a centralized or distributed database, and/or associated caches andservers) that store the one or more sets of instructions 222. The term“machine-readable media”, as used here, also refers to any medium thatis capable of storing, encoding or carrying a set of instructions 222for execution by the tag 200 and that cause the tag 200 to perform anyone or more of the methodologies of the present disclosure.

The input/output devices can include, but are not limited to, a display(e.g., an E Ink display, an LCD display and/or an active matrixdisplay), a speaker, a keypad and/or light emitting diodes. The displayis used to present item level information in a textual format and/orgraphical format. Similarly, the speaker may be used to output itemlevel information in an auditory format. The speaker and/or lightemitting diodes may be used to output alerts for drawing a person'sattention to the tag 200 (e.g., when motion thereof has been detected)and/or for notifying the person of a particular pricing status (e.g., onsale status) of the item to which the tag is coupled.

The clock/timer 214 is configured to determine a date, a time, and/or anexpiration of a pre-defined period of time. Technique for determiningthese listed items are well known in the art, and therefore will not bedescribed herein. Any known or to be known technique for determiningthese listed items can be used herein without limitation.

The tag 200 also comprises an optional location module 230. The locationmodule 230 is generally configured to determine the geographic locationof the tag at any given time. For example, in some scenarios, thelocation module 230 employs Global Positioning System (“GPS”) technologyand/or Internet based local time acquisition technology. The presentsolution is not limited to the particulars of this example. Any known orto be known technique for determining a geographic location can be usedherein without limitation including relative positioning within afacility or structure.

The optional coupler 242 is provided to securely or removably couple thetag 200 to an item (e.g., object 110 or 112 of FIG. 1). The coupler 242includes, but is not limited to, a mechanical coupling means (e.g., astrap, clip, clamp, snap) and/or adhesive (e.g., glue or sticker). Thecoupler 242 is optional since the coupling can be achieved via a weldand/or chemical bond.

The tag 200 can also include a power source 236, an optional ElectronicArticle Surveillance (“EAS”) component 244, and/or apassive/active/semi-passive RFID component 246. Each of the listedcomponents 236, 244, 246 is well known in the art, and therefore willnot be described herein. Any known or to be known battery, EAS componentand/or RFID component can be used herein without limitation. The powersource 236 can include, but is not limited to, a rechargeable batteryand/or a capacitor.

As shown in FIG. 2, the tag 200 further comprises an energy harvestingcircuit 232 and a power management circuit 234 for ensuring continuousoperation of the tag 200 without the need to change the rechargeablepower source (e.g., a battery). In some scenarios, the energy harvestingcircuit 232 is configured to harvest energy from one or more sources(e.g., heat, light, vibration, magnetic field, and/or RF energy) and togenerate a relatively low amount of output power from the harvestedenergy. By employing multiple sources for harvesting, the device cancontinue to charge despite the depletion of a source of energy. Energyharvesting circuits are well known in the art, and therefore will not bedescribed herein. Any known or to be known energy harvesting circuit canbe used herein without limitation.

As noted above, the tag 200 may also include a motion sensor 250. Motionsensors are well known in the art, and therefore will not be describedherein. Any known or to be known motion sensor can be used hereinwithout limitation. For example, the motion sensor 250 includes, but isnot limited to, a vibration sensor, an accelerometer, a gyroscope, alinear motion sensor, a Passive Infrared (“PIR”) sensor, a tilt sensor,and/or a rotation sensor.

The motion sensor 250 is communicatively coupled to the controller 210such that it can notify the controller 210 when tag motion is detected.The motion sensor 250 also communicates sensor data to the controller210. The sensor data is processed by the controller 210 to determinewhether or not the motion is of a type for triggering enablement of thecommunication device (e.g., transceiver) 206 or at least onecommunications operation. For example, the sensor data can be comparedto stored motion data 228 to determine if a match exists therebetween.More specifically, a motion pattern specified by the sensor data can becompared to a plurality of motion patterns specified by the storedmotion data 228. The plurality of motion patterns can include, but arenot limited to, a motion pattern for walking, a motion pattern forrunning, a motion pattern for vehicle transport, and/or a motion patternfor vibration caused by equipment or machinery in proximity to the tag(e.g., an air conditioner or fan). The type of movement (e.g., vibrationor being carried) is then determined based on which stored motion datamatches the sensor data. This feature of the present solution allows thetag 200 to selectively enable the communication device (e.g.,transceiver) or at least one communications operation only when thetag's location within a facility is actually being changed (e.g., andnot when a fan is causing the tag to simply vibrate).

In some scenarios, the tag 200 can be also configured to enter a sleepstate in which at least the motion sensor triggering of communicationoperations is disabled. This is desirable, for example, in scenarioswhen the tag 200 is being shipped or transported from a distributor to acustomer. In those or other scenarios, the tag 200 can be furtherconfigured to enter the sleep state in response to its continuousdetection of motion for a given period of time. The tag can betransitioned from its sleep state in response to expiration a definedtime period, the tag's reception of a control signal from an externaldevice, and/or the tag's detection of no motion for a period of time.

The power management circuit 234 is generally configured to control thesupply of power to components of the tag 200. In the event all of thestorage and harvesting resources deplete to a point where the tag 200 isabout to enter a shutdown/brownout state, the power management circuit234 can cause an alert to be sent from the tag 200 to a remote device(e.g., tag reader 120 or server 124 of FIG. 1). In response to thealert, the remote device can inform an associate (e.g., a storeemployee) so that (s)he can investigate why the tag 200 is notrecharging and/or holding charge.

The power management circuit 234 is also capable of redirecting anenergy source to the tag's 200 electronics based on the energy source'sstatus. For example, if harvested energy is sufficient to run the tag's200 function, the power management circuit 234 confirms that all of thetag's 200 storage sources are fully charged such that the tag's 200electronic components can be run directly from the harvested energy.This ensures that the tag 200 always has stored energy in caseharvesting source(s) disappear or lesser energy is harvested for reasonssuch as drop in RF, light or vibration power levels. If a sudden drop inany of the energy sources is detected, the power management circuit 234can cause an alert condition to be sent from the tag 200 to the remotedevice (e.g., tag reader 120 or server 124 of FIG. 1). At this point, aninvestigation may be required as to what caused this alarm. Accordingly,the remote device can inform the associate (e.g., a store employee) sothat (s)he can investigate the issue. It may be that other merchandiseare obscuring the harvesting source or the item is being stolen.

The present solution is not limited to that shown in FIG. 2. The tag 200can have any architecture provided that it can perform the functions andoperations described herein. For example, all of the components shown inFIG. 2 can comprise a single device (e.g., an Integrated Circuit(“IC”)). Alternatively, some of the components can comprise a first tagelement (e.g., a Commercial Off The Shelf (“COTS”) tag) while theremaining components comprise a second tag element communicativelycoupled to the first tag element. The second tag element can provideauxiliary functions (e.g., motion sensing, etc.) to the first tagelement. The second tag element may also control operational states ofthe first tag element. For example, the second tag element canselectively (a) enable and disable one or more features/operations ofthe first tag element (e.g., transceiver operations), (b) couple ordecouple an antenna to and from the first tag element, (c) bypass atleast one communications device or operation, and/or (d) cause anoperational state of the first tag element to be changed (e.g., causetransitioning the first tag element between a power save mode andnon-power save mode). In some scenarios, the operational state changecan be achieved by changing the binary value of at least one state bit(e.g., from 0 to 1, or vice versa) for causing certain communicationcontrol operations to be performed by the tag 200. Additionally oralternatively, a switch can be actuated for creating a closed or opencircuit. The present solution is not limited in this regard.

Referring now to FIG. 3, there is provided a detailed block diagram ofan exemplary architecture for a tag reader 300. Tag reader 120 of FIG. 1is the same as or similar to tag reader 200. As such, the discussion oftag reader 200 is sufficient for understanding tag reader 120.

Tag reader 300 may include more or less components than that shown inFIG. 3. However, the components shown are sufficient to disclose anillustrative embodiment implementing the present solution. Some or allof the components of the tag reader 300 can be implemented in hardware,software and/or a combination of hardware and software. The hardwareincludes, but is not limited to, one or more electronic circuits. Theelectronic circuit may comprise passive components (e.g., capacitors andresistors) and active components (e.g., processors) arranged and/orprogrammed to implement the methods disclosed herein.

The hardware architecture of FIG. 3 represents an illustration of arepresentative tag reader 300 configured to facilitate improvedinventory counts and management within an RSF (e.g., RSF 128 of FIG. 1).In this regard, the tag reader 200 comprises an RF enabled device 350for allowing data to be exchanged with an external device (e.g., RFIDtags 112 ₁, . . . , 112 _(N), 118 ₁, . . . , 118 _(X) of FIG. 1) via RFtechnology. The components 304-316 shown in FIG. 3 may be collectivelyreferred to herein as the RF enabled device 350, and may include a powersource 312 (e.g., a battery) or be connected to an external power source(e.g., an AC mains).

The RF enabled device 350 comprises an antenna 302 for allowing data tobe exchanged with the external device via RF technology (e.g., RFIDtechnology or other RF based technology). The external device maycomprise RFID tags 112 ₁, . . . , 112 _(N), 118 ₁, . . . , 118 _(X) ofFIG. 1. In this case, the antenna 302 is configured to transmit RFcarrier signals (e.g., interrogation signals) to the listed externaldevices, and/or transmit data response signals (e.g., authenticationreply signals) generated by the RF enabled device 350. In this regard,the RF enabled device 350 comprises an RF transceiver 308. RFtransceivers are well known in the art, and therefore will not bedescribed herein. However, it should be understood that the RFtransceiver 308 receives RF signals including information from thetransmitting device, and forwards the same to a logic controller 310 forextracting the information therefrom.

The extracted information can be used to determine the presence,location and/or type of movement of an RFID tag within a facility (e.g.,RSF 128 of FIG. 1). Accordingly, the logic controller 310 can store theextracted information in memory 304, and execute algorithms using theextracted information. For example, the logic controller 310 cancorrelate tag reads with beacon reads to determine the location of theRFID tags within the facility. The logic controller 310 can also performpattern recognition operations using sensor data received from RFID tagsand comparison operations between recognized patterns and pre-storedpatterns. The logic controller 310 can further select a time slot from aplurality of time slots based on a tag's unique identifier (e.g., anEPC), and communicate information specifying the selected time slot tothe respective RFID tag. The logic controller 310 may additionallydetermine a WOT during which a given RFID tag's communication device(e.g., transceiver) or operation(s) is(are) to be turned on when motionis detected thereby, and communicate the same to the given RFID tag. TheWOT can be determined based on environmental conditions (e.g.,temperature, time of day, etc.) and/or system conditions (e.g., amountof traffic, interference occurrences, etc.). Other operations performedby the logic controller 310 will be apparent from the followingdiscussion.

Notably, memory 304 may be a volatile memory and/or a non-volatilememory. For example, the memory 304 can include, but is not limited to,a RAM, a DRAM, an SRAM, a ROM, and a flash memory. The memory 304 mayalso comprise unsecure memory and/or secure memory. The phrase “unsecurememory”, as used herein, refers to memory configured to store data in aplain text form. The phrase “secure memory”, as used herein, refers tomemory configured to store data in an encrypted form and/or memoryhaving or being disposed in a secure or tamper-proof enclosure.

Instructions 322 are stored in memory for execution by the RF enableddevice 350 and that cause the RF enabled device 350 to perform any oneor more of the methodologies of the present disclosure. The instructions322 are generally operative to facilitate determinations as to whetheror not RFID tags are present within a facility, where the RFID tags arelocated within a facility, and/or which RFID tags are in motion at anygiven time. Other functions of the RF enabled device 350 will becomeapparent as the discussion progresses.

Referring now to FIG. 4, there is provided a detailed block diagram ofan exemplary architecture for a server 400. Server 124 of FIG. 1 is thesame as or substantially similar to server 400. As such, the followingdiscussion of server 400 is sufficient for understanding server 124.

Notably, the server 400 may include more or less components than thoseshown in FIG. 4. However, the components shown are sufficient todisclose an illustrative embodiment implementing the present solution.The hardware architecture of FIG. 4 represents one embodiment of arepresentative server configured to facilitate inventory counts andmanagement. As such, the server 400 of FIG. 4 implements at least aportion of a method for determining inventory using time slotted tagcommunications in accordance with the present solution.

Some or all the components of the server 400 can be implemented ashardware, software and/or a combination of hardware and software. Thehardware includes, but is not limited to, one or more electroniccircuits. The electronic circuits can include, but are not limited to,passive components (e.g., resistors and capacitors) and/or activecomponents (e.g., amplifiers and/or microprocessors). The passive and/oractive components can be adapted to, arranged to and/or programmed toperform one or more of the methodologies, procedures, or functionsdescribed herein.

As shown in FIG. 4, the server 400 comprises a user interface 402, a CPU406, a system bus 410, a memory 412 connected to and accessible by otherportions of server 400 through system bus 410, and hardware entities 414connected to system bus 410. The user interface can include inputdevices (e.g., a keypad 450) and output devices (e.g., speaker 452, adisplay 454, and/or light emitting diodes 456), which facilitateuser-software interactions for controlling operations of the server 400.

At least some of the hardware entities 414 perform actions involvingaccess to and use of memory 412, which can be a RAM, a disk driverand/or a Compact Disc Read Only Memory (“CD-ROM”). Hardware entities 414can include a disk drive unit 416 comprising a computer-readable storagemedium 418 on which is stored one or more sets of instructions 420(e.g., software code) configured to implement one or more of themethodologies, procedures, or functions described herein. Theinstructions 420 can also reside, completely or at least partially,within the memory 412 and/or within the CPU 406 during execution thereofby the server 400. The memory 412 and the CPU 406 also can constitutemachine-readable media. The term “machine-readable media”, as used here,refers to a single medium or multiple media (e.g., a centralized ordistributed database, and/or associated caches and servers) that storethe one or more sets of instructions 420. The term “machine-readablemedia”, as used here, also refers to any medium that is capable ofstoring, encoding or carrying a set of instructions 420 for execution bythe server 400 and that cause the server 400 to perform any one or moreof the methodologies of the present disclosure.

In some scenarios, the hardware entities 414 include an electroniccircuit (e.g., a processor) programmed for facilitating the provision ofa three-dimensional map showing locations of RFID tags within a facilityand/or changes to said locations in near real-time. In this regard, itshould be understood that the electronic circuit can access and run asoftware application 422 installed on the server 400. The softwareapplication 422 is generally operative to facilitate: the determinationof RFID tag locations within a facility; the direction of travel of RFIDtags in motion; and the mapping of the RFID tag locations and movementsin a virtual three dimensional space. Other functions of the softwareapplication 422 will become apparent as the discussion progresses. Suchother functions can relate to tag reader control and/or tag control.

Referring now to FIGS. 5-6, there are provided illustrations that areuseful for understanding certain advantages of the present solution. Asnoted above, the present solution provides RFID tags which can be readby a tag reader located farther away therefrom as compared to that ofconventional systems. FIG. 5 shows a tag reader layout for aconventional system. In FIG. 5, there are 20 tag readers 502 withoverlapping coverage areas 508. The distance 504, 506 between adjacenttag readers is relatively small (e.g., 9-15 feet apart). In contrast,FIG. 6 shows a tag reader layout for a system implementing the presentsolution. In FIG. 6, there are advantageously a significantly smallernumber of tag readers 602 needed to cover the same area. Accordingly,the distances 606, 608 (e.g., 90-150 feet apart) between adjacent tagreaders 602 is much greater than the distances 504, 506 of FIG. 5.Consequently, the present solution has a less resource intensive andless costly infrastructure.

Illustrative Methods for Locating an RF Enabled-Device in a Facility

Referring now to FIG. 7, there are provided illustrations that areuseful for understanding methods for determining inventory using timeslotted tag communications. As shown in FIG. 7A, a period of time 700(e.g., a 24 hour period) is segmented into a plurality of time slots 702₁, 702 ₂, . . . , 702 _(Y) having equal lengths (e.g., 1 second). Duringeach time slot, at least one RFID tag (e.g., RFID tag 112 ₁ of FIG. 1)(A) receives (“Rx”) an interrogation signal transmitted from a tagreader (e.g., tag reader 120 of FIG. 1) and (B) transmits (“Tx”) aresponse signal.

In some scenarios such as that shown in FIG. 7B, a single RFID tag isassigned to each time slot. For example, a first RFID tag is assigned tothe first time slot 702 ₁. A second RFID tag is assigned to a secondtime slot 702 ₂. A third RFID tag is assigned to a third time slot 702₃. This time slot assignment can be performed in accordance with achaotic, random or pseudo-random number algorithm. Alternatively, thetime slot assignment can be determined based on the unique codes of thetags (e.g., EPCs, Cyclic Redundancy Check (“CRC”) codes, hash codes oroutputs of randomizing algorithms). The time slot assignment can beperformed by the RFID tags (e.g., RFID tags 112 ₁, . . . , 112 _(N), 118₁, . . . , 118 _(X) of FIG. 1), tag readers (e.g., tag reader(s) 120 ofFIG. 1), and/or a remote server (e.g., server 124 of FIG. 1).

In some scenarios, the time slot allocations can be dynamically changedduring system operations. For example, a relatively large number of tagread collisions are occurring in the system (e.g., system 100 of FIG.1). Accordingly, the time slot allocations are changed so as to minimizesuch tag read collisions. The manner in which time slots arere-allocated can be determined by a single device (e.g., server 124 ofFIG. 1) or by a plurality of devices (e.g., RFID tags 112 ₁, . . . , 112_(N), 118 ₁, . . . , 118 _(X), tag readers 120 and/or server 124 of FIG.1).

Referring now to FIG. 8, there is a flow diagram of an illustrativemethod 800 for determining an inventory using a time slottedcommunications scheme such as that shown in FIGS. 7A-7B. Method 800begins with 802 and continues with 804-806 where an RFID tag (e.g., RFIDtags 112 ₁, . . . , 112 _(N), 118 ₁, . . . , or 118 _(X) of FIG. 1) isactivated and placed in a time slot determining mode.

In the time slot determining mode, the RFID tag is assigned to a timeslot (e.g., time slot 702 ₁ of FIG. 7) of a plurality of time slots(e.g., time slots 702 ₁, 702 ₂, . . . , 702 _(Y) of FIG. 7). This isachieved through (I) operations performed by the RFID tag and/or (II)operations performed by a remote device (e.g., tag reader 120 of FIG. 1or server 124 of FIG. 1).

In the first case (I), operations 808-810 are performed by the RFID tag.These operations involve: determining the RFID tag's unique code (e.g.,unique ID 224 of FIG. 2); and using the unique code to determine whichtime slot(s) the RFID tag should listen for an interrogation signal froma tag reader and respond to the same. In this regard, the RFID tag canbe programmed with an algorithm for translating the unique code to atime slot value or with a look-up table indicating a mapping of uniquecodes to time slot values. The translation can be achieved by using theunique code as an input to a pre-defined algorithm to compute a timeslot value.

In the second case (II), operations are performed by the remotedevice(s). These operations involve: selectively assigning at least onetime slot to the RFID tag; and communicating information identifying theselectively assigned time slot(s) to the RFID tag. The time slotassignment can be on a chaotic/random/pseudo-random algorithm and/or inaccordance with a unique code-to-time slot translation or mappingscheme. Accordingly, FIG. 8 includes optional block 812 where the RFIDtag receives time slot information from a remote device.

Upon completing 810 or 812, method 800 continues with 814 where anoperational mode of the RFID tag is transitioned from the time slotdetermining mode to a power recharging mode. In some scenarios, theoperational state or mode change is achieved by changing the binaryvalue of at least one state or mode bit (e.g., from 0 to 1, or viceversa) for causing certain communication control operations to beperformed by the RFID tag. Additionally or alternatively, a switch canbe actuated for creating a closed or open circuit. The present solutionis not limited in this regard.

In the power recharging mode, a rechargeable power source (e.g., powersource 236 of FIG. 2) is recharged using energy (e.g., RF energy)harvested by an energy harvesting circuit (e.g., energy harvestingcircuit 232 of FIG. 2) of the RFID tag. Notably, at least onecommunication operation and/or the RFID tag's communication device(e.g., communication device 206 of FIG. 2) is disabled or bypassed inthe power recharging mode. Other functions/operations of the RFID tagmay also be disabled in this mode for power conservation purposes.

Next, a decision is made as to whether it is time for the RFID tag tocommunicate with a tag reader. This decision can be achieved usingknowledge of the time slot(s) assigned to the particular tag. If it isnot the RFID tag's time to communicate with a tag reader [816:NO], thenmethod 800 returns to 816. In contrast, if it is the RFID tag's time tocommunicate with a tag reader [816:YES], then method 800 continues with818 where the operational mode of the RFID tag is transitioned from thepower recharging mode to a communications mode in which at least onecommunications operations and/or communication device (e.g.,transceiver) is enabled or no longer bypassed. Thereafter in 820, aninterrogation signal is received at the RFID tag. Interrogation signalsare well known in the art, and therefore will not be described herein.In response to the interrogation signal, the RFID tag generates andtransmits a tag response message, as shown by 822. Tag response messagesare well known in the art, and therefore will not be described herein.Still, it should be noted that the tag response message can include theRFID tag's unique identifier (e.g., unique identifier 224 of FIG. 2)therein. The present solution is not limited to the particulars of820-822. For example, a number of iterations of communicationsoperations (e.g., transmit and receive operations) can be performedprior to continuing to 824.

Next in 824, the operational mode of the RFID tag is transitioned backto the power recharging mode in which at least communications operationsand/or device (e.g., transceiver) is/are disabled and/or bypassed.Subsequently, 826 is performed where method 800 ends or other processingis performed (e.g., return to 806).

The method 800 described above provides a solution to real timeinventory, but does not include a way to detect changes to inventory dueto removal of RFID tags from an RSF (e.g., RSF 128 of FIG. 1) betweenrespective adjacent time slots (e.g., because of sale or theft).Accordingly, method 800 can be modified to include additional operationsfor detecting and accounting for tag movement at all times during aninventorying process. Such a modified method is discussed below inrelation to FIGS. 9-13.

Referring now to FIG. 9, there is provided an illustration that isuseful for understanding methods for determining inventory using motiontriggered time slotted tag communications. As shown in FIG. 9, the thirdtag performs communication (e.g., transceiver) operations in time slots702 _(V), 702 _(V+1), 702 _(V+2) in addition to its assigned time slot702 ₃. These time slots 702 _(V), 702 _(V+1), 702 _(V+2) occur during aperiod of time when the third tag is in motion. This allows tag readersto see moving RFID tags quickly, as well as helps at a Point Of Sale(“POS”) and to determine whether the RFID tags were moved into a highrisk area (e.g., a fitting room or bathroom).

Referring now to FIGS. 10-11, there are provided illustrations that areuseful in understanding the contents of tag response messages. In somescenarios, the tag response message 1000 includes only a unique tagidentifier 1002 (e.g., unique ID 224 of FIG. 2). In other scenarios, thetag response message 1100 includes a motion indicator 1104 in additionto the unique tag identifier 1102. The motion indicator 1104 indicateswhether the tag is currently in motion, is in a given operationalstate/mode, and/or has a given motion sensor state.

Referring now to FIG. 12, there is provided a flow diagram of anillustrative method 1200 for determining inventory using time slottedtag communications. Method 1200 begins with 1202 and continues with1204-1224. 1204-1224 are the same as or substantially similar to 804-824of FIG. 8. The above discussion of 804-824 is sufficient forunderstanding 1204-1224. Notably, a new block 1217 is provided in whichmethod 800 continues to 1226 of FIG. 12B when a determination is made in1216 that it is not the RFID tag's time to communicate with the tagreader.

Upon completing 1224, method 1200 continues with 1226 of FIG. 12B. Asshown in FIG. 12B, 1226 involves performing operations by a motionsensor (e.g., motion sensor 250 of FIG. 2) to detect motion of the RFIDtag (e.g., RFID tag 112 ₁, . . . , 112 _(N), 118 ₁, . . . , or 118 _(X)of FIG. 1). Next in 1228, the motion sensor performs operations tonotify a controller (e.g., controller 210 of FIG. 2) of the RFID tagthat motion has been detected. The motion sensor also provides motionsensor data to the controller. In 1230, the motion sensor data isanalyzed to determine if the RFID tag is traveling through a facility.This analysis can be performed by the RFID tag's controller and/or aremote device (e.g., a tag reader or server). The analysis can involvedetecting pre-defined patterns of movement specified in the motionsensor data (e.g., a walking pattern, a running pattern, or a vehicletraveling pattern). If a determination is made that the RFID tag is nottraveling through a facility (e.g., RSF 128 of FIG. 1) [1232:NO], then1234 is performed where method 1200 ends or other processing isperformed (e.g., return to 1226).

In contrast, if a determination is made that the RFID tag is travelingthrough a facility [1232:YES], then 1236 is optionally performed where aWOT is determined during which the RFID tag's communication operation(s)and/or communication device (e.g., transceiver) is to be operational,enabled or no longer bypassed. 1236 is optional since the RFID tag canbe pre-programmed with a WOT value. In other scenarios, a value for theWOT is determined by the RFID tag and/or a remote device. The WOT valueis determined based on environmental conditions and/or systemconditions. Notably, the WOT value is variable. This feature of thepresent solution allows minimization of the RFID tag's system power,minimizes tag read collisions, and identification of moving RFID tagswithout reading all static/stationary RFID tags.

Once the RFID tag has knowledge of the WOT value, then 1238 is performedwhere its operational mode is transitioned from the power rechargingmode to the communications mode in which at least one communicationoperation and/or communication device (e.g., transceiver) is enabled orno longer bypassed. In the communications mode, the RFID tag uses aninternal clock/timer (e.g., clock/timer 214 of FIG. 1) to determine ifthe WOT has expired. If not [1240:NO], then the RFID tag performsoperations in 1242 to receive and respond to at least one interrogationsignal. In so [1240:YES], then 1226-1242 are repeated until motion is nolonger detected, a stationary state signal has been communicated fromthe tag to a tag reader, a power source (e.g., power source 236 of FIG.2) has a certain level of charge, and/or a control signal is receivedfrom an external device to disable or bypass the communicationoperations and/or device (e.g., transceiver). Subsequently, 1246 isperformed where method 1200 ends or other processing is performed (e.g.,return to 1214 of FIG. 12A).

The present solution has many advantages. For example, the presentsolution: solves real time, daily, accurate inventory with a low costtag reader infrastructure; solves an overhead RFID as EAS problem; isable to accurately track moving tags; identify tags leaving a store evenwhen there are a relatively large number of tags in proximity to theexit; and improves ecommerce processes by providing accurate inventorycount and RFID tag locations at all times. The present solution is alsogreener since it limits the amount of time RF devices are enabled.

The present solution can be used in conjunction with other sensors, suchas proximity sensors. For example, if proximity sensors detect thepresence of individuals in the facility, then the stationary tag readerscan be temporarily disabled (e.g., until there are no more people in thefacility).

The RFID tags of the present solution are relatively small with goodread range. This allows the RFID tags to be added to animals (e.g.,humans, pets, etc.). In this case, the RFID tags can be configured tohave enabled communication operations and/or devices (e.g.,transceivers) only during times of detected movement thereof. The RFIDtags could also be placed on wearable items (e.g., hats, belts, etc.) ina manner that does not interfere with the wearing humans.

Although the present solution has been illustrated and described withrespect to one or more implementations, equivalent alterations andmodifications will occur to others skilled in the art upon the readingand understanding of this specification and the annexed drawings. Inaddition, while a particular feature of the present solution may havebeen disclosed with respect to only one of several implementations, suchfeature may be combined with one or more other features of the otherimplementations as may be desired and advantageous for any given orparticular application. Thus, the breadth and scope of the presentsolution should not be limited by any of the above describedembodiments. Rather, the scope of the present solution should be definedin accordance with the following claims and their equivalents.

What is claimed is:
 1. A method for determining an inventory,comprising: placing a Radio Frequency Identification (“RFID”) tag in afirst operational mode in which at least one communication operation ordevice of the RFID tag is disabled or bypassed; performing firstoperations by the RFID tag to determine when it is time to begincommunications in accordance with the time slotted communicationsscheme; transitioning an operational mode of the RFID tag from the firstoperational mode to a second operational mode in which the at least onecommunication operation or device of the RFID tag is enabled or nolonger bypassed, in response to a determination that it is time for theRFID tag to begin communications; and transitioning the operational modeof the RFID tag back into the first operational mode when the RFID tag'scommunications with a remote tag reader for inventory determinationpurposes are complete or a time slot has expired.
 2. The methodaccording to claim 1, wherein the first operational mode comprises apower recharging mode in which a rechargeable power source is chargedusing harvested ambient energy.
 3. The method according to claim 1,further comprising assigning at least one first time slot of a pluralityof time slots to each RFID tag of a plurality of RFID tags in accordancewith the time slotted communication scheme.
 4. The method according toclaim 3, wherein the at least one time slot is assigned to the RFID tagbased on the RFID tag's unique code.
 5. The method according to claim 4,wherein the RFID tag's unique code comprises an Electronic Product Code(“EPC”), a Cyclic Redundancy Check (“CRC”) code, a hash code or outputof a randomizing algorithm.
 6. The method according to claim 3, whereinthe at least one time slot is assigned to the RFID tag based a chaotic,random or pseudo-random algorithm.
 7. The method according to claim 1,further comprising performing communication operations by the RFID tagin time slots of the plurality of time slots that are allocated to otherRFID tags, when the RFID tag is in motion.
 8. The method according toclaim 7, further comprising discontinuing the communication operationswhen motion is no longer detected, a power source of the RFID tag has acertain level of charge, or a control signal for disabling or bypassingthe communication operations is received from an external device.
 9. Themethod according to claim 1, further comprising performing operations bya motion sensor to detect motion of the RFID tag.
 10. The methodaccording to claim 9, further comprising transitioning the operationalmode of the RFID tag from the first operational mode to the secondoperational mode, in response to the detected motion of the RFID tag.11. The method according to claim 10, further comprising transitioningthe operational mode of the RFID tag from the first operational mode tothe second operational mode, in response to a determination that thedetected motion is of a type for triggering communication operations ordevice enablement.
 12. The method according to claim 11, furthercomprising performing operations by the RFID tag to notify the remotetag reader that motion has been detected by the motion sensor.
 13. Themethod according to claim 11, further comprising transitioning the RFIDtag back into the first operational mode when a window of time hasexpired.
 14. The method according to claim 13, wherein a value of thewindow of time is variable.
 15. The method according to claim 14,wherein the value of the window of time is dynamically determined basedon at least one of an environmental condition and the system operationalcondition.
 16. A method for determining an inventory, comprising:placing a tag in a first operational mode in which at least onecommunication operation or device of the tag is disabled or bypassed;performing first operations by the tag to determine when it is time tobegin communications in accordance with the time slotted communicationsscheme; transitioning an operational mode of the tag from the firstoperational mode to a second operational mode in which the at least onecommunication operation or device of the tag is enabled or no longerbypassed, in response to a determination that it is time for the tag tobegin communications; and transitioning the operational mode of the tagback into the first operational mode when the tag's communications witha remote tag reader for inventory determination purposes are complete ora time slot has expired.
 17. A Radio Frequency Identification (“RFID”)tag, comprising: a processor; and a non-transitory computer-readablestorage medium comprising programming instructions that are configuredto cause the processor to implement a method for determining aninventory, wherein the programming instructions comprise instructionsto: place the RFID tag in a first operational mode in which at least onecommunication operation or device of the RFID tag is disabled orbypassed; perform first operations to determine when it is time to begincommunications in accordance with the time slotted communicationsscheme; transition an operational mode of the RFID tag from the firstoperational mode to a second operational mode in which the at least onecommunication operation or device of the RFID tag is enabled or nolonger bypassed, in response to a determination that it is time for theRFID tag to begin communications; and transition the operational mode ofthe RFID tag back into the first operational mode when the RFID tag'scommunications with a remote tag reader for inventory determinationpurposes are complete or a time slot has expired.
 18. The RFID tagaccording to claim 17, wherein the first operational mode comprises apower recharging mode in which a rechargeable power source is chargedusing harvested ambient energy.
 19. The RFID tag according to claim 17,wherein the programming instructions further comprise instructions toassign at least one first time slot of a plurality of time slots to eachRFID tag of a plurality of RFID tags in accordance with the time slottedcommunication scheme.
 20. The RFID tag according to claim 19, whereinthe at least one time slot is assigned to the RFID tag based on the RFIDtag's unique code.
 21. The RFID tag according to claim 20, wherein theRFID tag's unique code comprises an Electronic Product Code (“EPC”), aCyclic Redundancy Check (“CRC”) code, a hash code or output of arandomizing algorithm.
 22. The RFID tag according to claim 19, whereinthe at least one time slot is assigned to the RFID tag based a chaotic,random or pseudo-random algorithm.
 23. The RFID tag according to claim17, wherein the programming instructions further comprise instructionsto cause communication operations to be performed by the RFID tag intime slots of the plurality of time slots that are allocated to otherRFID tags, when the RFID tag is in motion.
 24. The RFID tag according toclaim 23, wherein the programming instructions further compriseinstructions to discontinue the communication operations when motion isno longer detected, a power source of the RFID tag has a certain levelof charge, or a control signal for disabling or bypassing thecommunication operations is received from an external device.
 25. TheRFID tag according to claim 17, wherein the programming instructionsfurther comprise instructions to cause operations to be performed by amotion sensor to detect motion of the RFID tag.
 26. The RFID tagaccording to claim 25, wherein the programming instructions furthercomprise instructions to transition the operational mode of the RFID tagfrom the first operational mode to the second operational mode, inresponse to the detection motion of the RFID tag.
 27. The RFID tagaccording to claim 26, wherein the programming instructions furthercomprise instructions to transition the operational mode of the RFID tagfrom the first operational mode to the second operational mode, inresponse to a determination that the detected motion is of a type fortriggering communication operations or device enablement.
 28. The RFIDtag according to claim 27, wherein the programming instructions furthercomprise instructions to notify the remote tag reader that motion hasbeen detected by the motion sensor.
 29. The RFID tag according to claim27, wherein the programming instructions further comprise instructionsto transition the RFID tag back into the first operational mode when awindow of time has expired.
 30. The RFID according to claim 29, whereina value of the window of time is variable.
 31. The RFID tag according toclaim 30, wherein the value of the window of time is dynamicallydetermined based on at least one of an environmental condition and thesystem operational condition.